anti-epileptics

Question 1

what are the 3 classes of seizures

Answer 1

generalised, partial and status

Question 2

what are the 4 types of generalised seizures

Answer 2

tonic clonic (grand mal)
absence (petit mal)
myoclonic
atonic

Question 3

what are the 2 types of partial seizures

Answer 3

simple (consciousness not impaired)

complex (consciousness impaired)

Question 4

what is the rationale for anti-epileptics

Answer 4

decrease membrane excitability by altering Na+ and Ca2+ conductance during action potentials

Question 5

how does phenytoin work

Answer 5

blockage of voltage dependent Na+ channels

Question 6

what is phenytoin suitable for

Answer 6

all types except absence seizures

Question 7

what is the caution of phenytoin

Answer 7

relatively narrow therapeutic range, saturation kinetics and consequent non-linear relationship between dose and plasma conc (needs titration and monitoring)
NO PREGGO

Question 8

how does carbamazepine work

Answer 8

blockage of voltage-dependent Na+ channels

Question 9

what is carbamazepine suitable for

Answer 9

all seizures except absence seizures

Question 10

cautions of carbamazepine

Answer 10

hepatic enzyme (CYP450) inducer 
half life shortens with repeated doses --> acclerates elimination of other drugs

Question 11

SE of carbamazepine

Answer 11

aplastic anemia

Question 12

how does valproate work

Answer 12

blockage of voltage dependent Na+ and Ca2+ channels

also inhibits GABA transaminase –> increased GABA

Question 13

what is valproate suitable for

Answer 13

all types of seizures

Question 14

cautions of valproate

Answer 14

strongly bound to plasma proteins, displaces other anti epileptics

Question 15

dose related ADR of antiepileptics

Answer 15

drowsiness, confusion, nystagmus, ataxia, slurred speech, nausea, unusual behaviour, mental changes, coma

Question 16

non-dose related ADR of anti epileptics

Answer 16

hirsutism, acne, gingival hyperplasia, folate deficiency, osteomalacia, hypersensitivity reactions

Question 17

benzos that can be used in epilepsy

Answer 17

clonazepam, lorazepam and diazepam (intermediate to long acting)

Question 18

which antiepileptic drug should be chosen initially

Answer 18

individualised
monotherapy. if fail, monotherapy of another drug should be tried
all drugs have similar efficacy in newly diagnosed epilepsy
carbamazepine, phenytoin and sodium valproate can be considered first line for newly diagnosed partial and generalised tonic clonic seizures

Question 19

when are antiepileptic drug levels tested

Answer 19

assessment of compliance to drug treatment for patients with refractory epilepsy
assessment of symptoms due to possible drug toxicity
titration of phenytoin dose